There is known, an apparatus that projects measurement light onto a fundus of a patient's eye, receives the measurement light reflected, therefrom by a two-dimensional light-receiving element, and measures eye refractive power of the patient's eye based on the result of the light reception (detection result). In such, an apparatus, an infrared light-emitting diode (LED) is usually used as a light source (measurement light source) for projecting measurement light.
In the meanwhile, the light source and the light-receiving element are arranged in positions conjugate with the fundus (e.g. with the fundus of an emmetropic eye). Where the LED is used as the light source, measuring accuracy is problematically worsened by luminance decrease, light noise effect and the like because it is greater in size as a light source and the luminous flux of measurement light is greater in diameter.
Meanwhile, because of absorption of the measurement light and attenuation of its reflection light, there is a difficulty in obtaining a sufficient light-amount at the light-receiving element. Particularly, as for infrared light, there is a problem of light-amount deficiency because light-receiving sensitivity is considerably low at the light-receiving element.
It is a technical problem of the present invention to provide an eye refractive power measurement apparatus capable of accurately obtaining a measurement result, in view of the problem as encountered in the prior art.